PRAIRIE VILLAGE, KS — Who is Joni Ernst?

According to media reports, she’s a “Harley-riding, pistol-packing,” “hog-castrating” farmer, Iraq veteran, and “magnetic mom” who projects “authenticity” and a “just-folks personality;” who “burst from relative obscurity—indeed, “literally came out of nowhere—and won Iowa’s Republican Senate primary against a millionaire self-funder; and who is now running even in general-election polling against another deep-pocketed opponent, a trial lawyer and four-term congressman who stands accused of sexism and elitism.

Ernst may be all those things. She’s also something else that has been largely overlooked in the media narrative about her scrappy-underdog status: the beneficiary of more than $1 million in spending from outside groups, according to the Center for Responsive Politics.

Stories from The Associated PressThe Des Moines RegisterKCRG-TV, and the Sioux City Journal about Ernst’s June 3 primary win all prominently noted the big spending by her main GOP rival, Mark Jacobs, who put an Iowa-record $3 million of his own money into the race, but did not mention the big spending that was made on Ernst’s behalf by outside groups to help her level the playing field. Neither did a Register editorial on June 14, which cited Ernst’s victory as evidence that “‘big money’ isn’t getting much for those campaign donations.” Another story from the Register in the wake of the primary did mention the role of outside spending in its closing grafs.

In fairness, the bulk of the outside spending for Ernst was a late development in the primary. But by the end of May, it was no secret.

On May 25, the Register’s Jennifer Jacobs signaled that a “cavalry” of outside spending was coming to aid Ernst, mentioning Sen. Marco Rubio’s Reclaim America PAC and the names of some other groups.

On May 29, Ed Tibbetts of the Quad-City Times reported that outside groups were spending $700,000 to boost Ernst in the final weeks of the primary—“a figure that far exceeds what she is spending herself in the closing days of the race.” Tibbetts also identified many of the groups, and their backers, by name: Along with the US Chamber of Commerce and Rubio’s PAC, there was the American Heartland PAC, funded by New York hedge fund executive Robert Mercer, and Senate Conservatives Action, founded by former Sen. Jim DeMint. Tibbetts also noted that on the Democratic side, Senate Majority PAC, linked to Senate Majority Leader Harry Reid, was pumping money into the race on behalf of Ernst’s general election opponent, Bruce Braley. This week, the League of Conservation Voters and other environmental groups also joined the fray, and the Center for Responsive Politics now counts nearly $1 million in outside spending opposing Ernst.

When I contacted him for this story, Tibbetts was quick to downplay his own efforts and credit his fellow Iowa reporters. He praised the Register’s Jacobs for her May 25 piece. But among the Iowa reporters whose coverage I’ve reviewed, Tibbetts has been most dogged about tracking the role of outside groups—and most insistent about trying to “name names” of those outside spenders.

When he couldn’t find out much about an organization, as in early reports on groups known as Trees of Liberty and American Heartland PAC, Tibbetts took the time to write about what he wasn’t finding. (One of his articles was linked by The New York Times’ Derek Willis to illustrate the difficulty in timely tracking of the sources outside spending, given lax disclosure requirements.) He also kept at it. In the case of American Heartland, FEC disclosures eventually allowed Tibbetts to identify the group’s primary backer as New York City hedge fund exec Robert Mercer (rather ironic, given that the super PAC’s advertising slammed Mark Jacobs for being a “Texas millionaire”).

Once he had identified Mercer, Tibbetts made sure to identify him again in subsequent stories when the PAC was mentioned—his practice is to identify the source of political cash, not just the groups spending it, whenever possible.

“Iowans deserve to know who they are,” he told me, “and that’s why I write about it.”

Still, Tibbetts said, the story remains incomplete.

“I think that myself and all of us probably could do more to explain why these groups are spending what they’re spending,” he said. When he tried to uncover Mercer’s motivation, he said, “I just couldn’t find that out.”

It’s not an academic question. Based on what we do know about the late surge in outside support for Ernst, at least a good chunk of it can probably be understood as “party money.” Her primary campaign really had been a surprising success, but given her limited fundraising a victory wasn’t assured, and different factions of the national Republican Party—impressively from her perspective, both tea party-aligned and more “establishment” groups—jumped in to get on the bandwagon, consolidate her new front-runner status, and push her across the finish line.

Deron Lee is CJR's correspondent for Iowa, Missouri, Kansas, and Nebraska. A writer and copy editor who has spent seven years with the National Journal Group, he has also contributed to The Hotline and the Lawrence Journal-World. He lives in the Kansas City area. Follow him on Twitter at @deron_lee.